The number of shark bites in Florida plummeted in 2018 with scientists pointing to a possible decrease in shark populations in coastal Atlantic waters as one reason for the decline.

Just 16 unprovoked shark bites were reported in Florida last year, compared to 31 the previous year, according to a report released this week by the University of Florida’s International Shark Attack File.

Even Volusia County, where a popular surf break near an inlet has given it the title of “shark attack capital of the world”, had just four bites, compared to nine in 2017.

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Year-to-year fluctuations in shark bites are normal, but 2018’s steep decline is unusual, said Gavin Naylor, director of the Florida Museum of Natural History’s shark research program.

Globally, 66 shark attacks were recorded last year, compared to 88 in 2017. That’s a 33 percent decrease and a 26 percent drop from the most recent five-year-average of 84 annual bites.

“Statistically, this is an anomaly,” Naylor said. “It begs the question of whether we’re seeing fewer bites because there are fewer sharks. Or it could be that the general public is heeding the advice of beach safety officials.”

Naylor cited the “apparent shrinking of Florida’s blacktip shark populations” as a reason for the reduction in bites statewide.

The phenomenon has been documented by Florida Atlantic University researcher Stephen Kajiura, who has flown the coastline from Boca Raton to Jupiter during blacktip shark season for eight years.

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In 2018, the largest number of sharks counted on any given flight was 2,800.

That's down from 12,130 in 2011, a 76 percent reduction that has been on a slow dive since the counts began.

"It's dramatic," Kajiura said in an interview this past summer.

Blacktips, which come to Florida during the winter seeking warmer waters, are responsible for about 20 percent of the bites in Florida. Bull sharks also make up about 20 percent of Florida bites, while spinner sharks come in 3rd with 16 percent.

Kajiura said the lower blacktip numbers directly correlate with higher water temperatures.

In 2011, the mean water temperature along the blacktip's Palm Beach County route was 73.9 degrees. Last year, the mean temperature was 75.3 degrees.

Bottom line: The sharks may be finding their ideal temperature farther north.

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Mark Bond, a marine researcher at Florida International University, said slight environmental changes such as where their food is swimming or water temperature increases could lead sharks away from bathers.

But one year of fewer bites doesn’t make a trend, he said. In the past 10 years, shark bites worldwide have fluctuated from a low of 55 in 2008 to a high of 98 in 2015.

In Florida, 2017 saw the highest bites in the past decade with 34, including 5 in Palm Beach County.

“I think it will be interesting to visit this again in a couple years and look to see what the numbers are,” Bond said. “It's difficult to make a statement based on a single  year.”

Four of the shark bites worldwide in 2018 proved fatal, compared to the annual average of six deaths.

One person was killed by a white shark in Cape Cod — the first shark-related death for the community in 82 years, according to this week’s report.

“An increase in sharks is a symptom of restoring healthy oceans,” Naylor said, noting that great whites are returning to Cape Cod as seal populations rebound.

Palm Beach County had one shark bite last year when a kiteboarder was bitten between the Juno Beach Pier and the Loggerhead Marine Life Center, said Tyler Bowling, manager of the Florida Program for Shark Research.

The county comes in third statewide for the total number of shark bites with 76 incidents in records that date back to 1882. Volusia has the highest number of bites at 303, with Brevard as runner-up with 147.

One reason for Palm Beach County’s high numbers could be its close proximity to the warm current of the Gulf Stream.

“The Gulf Stream will control where the prey is,” Bond said. “And that will control where the sharks are.”

Kmiller@pbpost.com

@KmillerWeather